• Archives of Reconstructive Microsurgery
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• 제16권1호
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• pp.14-22
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• 2007

Perforator free flap (PFF) is currently a major reconstructive option for soft tissue reconstruction in adults. Although PFFs have been used commonly, most reconstructive surgeons still hesitate to perform PFFs in children. The main cause of concern is the perceived high failure rate related to the small diameter of children's perforator vessels. We present 8 consecutive cases of successful transfer of thoracodorsal artery (TDA) & anterolateral thigh (ALT) perforator flap in children. Between 2003 and 2005, 8 children(4 to 13 years old) with soft tissue defects of the extremities were reconstructed with TDA & ALT PFFs. All flaps completely survived. There were no problems relating to vascular spasm or occlusion. Range of motion of reconstructed extremities were fully recovered. Among 8 patients, only 1 patient was performed an additional flap thinning procedure. 8 cases of TDA & ALT perforator flaps were successfully transferred in children. PFF is an excellent option in reconstruction of children as well as in adults because of its thinness, long pedicle length, least donor site morbidity and acceptable donor site scar.

• 한국식품영양학회지
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• 제25권1호
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• pp.50-56
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• 2012

This paper examines the effects of various methods of soft steaming(i.e., forced convection-boiler, forced convection-fan, and natural convection) on the quality of potatoes. In particular, the paper investigates the effects of cooking conditions (the steaming method, the treatment time, and the temperature) on the color(L, a, b), moisture content, texture profile, and ascorbic acid of potatoes. The results indicate that not only the cooking method, the treatment time, and the temperature but also the heat transfer mechanism had considerable influence on potato quality. In addition, natural convection steaming was superior to other treatment methods in terms of nutrient retention and texture maintenance. The results of this study should be useful for establishing commercial standards for processing potatoes and improving the quality of thermally processed foods.

• Archives of Reconstructive Microsurgery
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• 제3권1호
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• pp.54-63
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• 1994

Pulp and palm of the hand and heel of the sole are anatomically unique. Satisfactory reconstruction of these areas presents the plastic surgeon with many challenges and requires durable and sensible skin coverage, minimal donor morbidity and reliable operative procedure. We presents 7 clinical cases of sensate instep free flap transfer in this paper during the last 2 years. Three cases were soft tissue defects due to crushing and avulsion injury on the pulp of finger. 1 case was unstable scar and redundant flap after reconstruction of soft tissue dect of palm and 1 case was contracture of first web of hand. One case was a soft tissue defect due to avulsion injury on heel. Lastly, one case was chronic osteomyelitis with open wound on lateral malleolar area. Follow-up period ranged from 3 months to 2 years. Through the whole follow-up period, all flaps were viable and durable to persistant stress or weight bearing and were sensible enough to porotect the recocstructed area from injuries and maintain functions. In conclusions, the instep free flap should be considered as a valuable tool in reconstruction of hand and extremity requiring durability and sensation.

• Journal of Power Electronics
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• 제13권2호
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• pp.177-185
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• 2013

This paper studies a soft switching DC/DC converter to achieve zero voltage switching (ZVS) for all switches under a wide range of load condition and input voltage. Two three-level PWM circuits with the same power switches are adopted to reduce the voltage stress of MOSFETs at $V_{in}/2$ and achieve load current sharing. Thus, the current stress and power rating of power semiconductors at the secondary side are reduced. The series-connected transformers are adopted in each three-level circuit. Each transformer can be operated as an inductor to smooth the output current or a transformer to achieve the electric isolation and power transfer from the input side to the output side. Therefore, no output inductor is needed at the secondary side. Two center-tapped rectifiers connected in parallel are used at the secondary side to achieve load current sharing. Due to the resonant behavior by the resonant inductance and resonant capacitance at the transition interval, all switches are turned on at ZVS. Experiments based on a 1kW prototype are provided to verify the performance of proposed converter.

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.423-426
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• 2006

A developed neutron activation analysis(NAA) and gamma-spectrometry were applied to improve the analytical sensitivity and precision of impurities in electronic-circuit raw materials. It is well known that soft errors in high precision electronic circuits can be induced by alpha particles emitted from naturally occurring radioactive impurities such as U and Th. As electronic circuits have recently become smaller in dimension and higher in density, these alpha-particle emitting radioactive impurities must be strictly controlled. Therefore, new NAA methods have been established using a HTS(Hydraulic Transfer System) irradiation facility and a background reduction method. For eliminating or stabilizing fluctuated background caused by Rn-222 and its progeny nuclides in air, a nitrogen purging system is used. Using the developed NAA and gamma-spectrometry, ultra trace amounts of U(0.1ng/g) and Th(0.01ng/g) in an alumina ball and high purity silica used for an epoxy molding compound (EMC) could be determined.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.409-429
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• 2006

In designing rock-socketed drilled shaft, bearing capacity evaluation is very important because the maximum values of base and side resistance are not generally mobilized at the same value of displacement, FHWA and AASHTO code suggest different ultimate bearing capacity formular according to rock type and shaft settlement. In domestic code suggest base resistance and side resistance can be added on condition that after confirming the result of field load test with axial load transfer test. This paper shows that static load test and hi-directional load test result analysis of deep rock-socketed drilled shaft in three different sites. Load-settlement curve, t-z, and q-w curve in rock-socketed part were calculated and compared. t-z curve in weathered and soft rock showed no deflection softening behavior in pretty large strain (about 2-3% of diameter). Ultimate resistance could be the summation of side resistance and base resistance in rock-socketed drilled shaft in domestic sites.

• 대한치과교정학회지
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• 제53권1호
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• pp.54-64
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• 2023

This case report describes skeletal anchorage-supported maxillary protraction performed with the Alternate Rapid Maxillary Expansion and Constriction (AltRAMEC) protocol over a treatment duration of 14 months in a 16-year-old female patient who was in the late growth-development period. Miniplates were applied to the patient's aperture piriformis area to apply force from the protraction appliance. After 9 weeks of following the Alt-RAMEC protocol, miniplates were used to transfer a unilateral 500-g protraction force to a Petit-type face mask. A significant improvement was observed in the soft tissue profile in measurements made both cephalometrically and in three dimensional photographs. Subsequently, the second phase of fixed orthodontic treatment was started and the treatment was completed with the retention phase. Following treatment completion, occlusion, smile esthetics, and soft tissue profile improved significantly in response to orthopedic and orthodontic treatment.

• 한국지반공학회논문집
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• 제16권1호
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• pp.131-143
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• 2000

연약지반속에 말뚝을 설치하고 성토를 실시할 경우 말뚝에 작용하는 연직하중을 산정할 수 있는 이론적 해석법을 개발하였다. 여기서 말뚝은 성토하중지지 효과를 증대시키기 위하여 일정간격의 줄말뚝 형태로 설치하며 각 줄말뚝의 두부는 지중보 형태의 말뚝캡보로 연결시킨 경우를 대상으로 한다. 이론식의 유도과정에서 성토지지말뚝으로 지지된 성토지반의 파괴발생 기구를 말뚝위 성토지반속의 파괴형태에 따라 지반아칭파괴와 펀칭전단파괴의 두 가지로 크게 구분하였다. 여기서 지반아칭은 말뚝캡보 사이의 간격이 좁거나 성토고가 충분히 높을 때 발생된다. 지반아칭파괴는 아치의 파괴부위에 따라 정상파괴와 캡파괴로 나누어 각 파괴형태의 안전성이 검토되었다. 또한, 제안식에 의한 성토지지말뚝의 하중분담효과는 말뚝캡보의 간격과 폭의 크기 및 지반정수에 크게 영향을 받고 있음을 알 수 있다. 즉, 말뚝캡보의 간격이 증가하면 말뚝의 하중분담효과는 감소하며 성토고, 말뚝캡보폭, 내부마찰각 및 점착력의 크기가 증가할수록 하중분담효과가 커지게 된다. 따라서 이러한 말뚝 및 지반에 관한 영향요소를 적절히 결정하면 성토지지말뚝의 성토하중분담 효과를 효과적으로 극대화시킬 수 있을 것이다.

• 한국지반공학회논문집
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• 제21권10호
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• pp.5-16
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• 2005

토목섬유로 보강된 성토지지말뚝공법은 기존 성토지지말뚝공법의 말뚝간격처리 및 말뚝캡 면적문제를 개선하며 효과적으로 지지력을 보강하고 특히 전체침하 및 부등침하 감소시킬 수 있는 공법으로 최근 활용이 증가하고 있다. 본 연구에서는 지오그리드로 보강된 성토지지말뚝공법의 보강 및 아칭효과에 대하여 연구하기 위하여 지오그리드 보강유무, 말뚝간격변화에 따른 현장모형실험과 2차원 수치해석을 수행하였다. 수치해석적 연구는 범용 유한차분해석 프로그램인 FLAC 2-D를 사용하였으며, 지반-말뚝-지오그리드의 하중전달 메카니즘에 대하며 분석하였다. 지오그리드로 보강된 성토지지말뚝의 하중전달은 성토제체 내의 아칭효과, 지오그리드의 인장, 말뚝으로의 응력전이 등의 과정이 복합적으로 발생한다. 현장모형실험 및 수치해석연구 결과에 따르면 지오그리드의 보강에 따라 아칭효과는 미소하게 감소하지만, 부등침하는 급격히 감소하는 것으로 나타났다. 또한, D/b=3(D: 말뚝캡 간격, b: 말뚝직경)일때 무보강 지반에 비하여 $40\%$의 침하가 감소하며, D/b=6이상일 경우는 지오그리드에 의한 하중전이가 발생하지 않아 보강효과가 거의 없는 것으로 나타났다.

• Tuberculosis and Respiratory Diseases
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• 제49권2호
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• pp.189-197
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• 2000

연구배경 : 폐암은 진단 당시 이미 국소 침윤이나 원격 전이가 된 경우가 많고 이에 대한 적절한 치료법이 없기 때문에 예후가 불량하다. TIMP(tissue inhibitor of metalloproteinase)는 암세포의 침윤 및 전이에 중요한 역할을 하는 metalloproteinase를 억제하는 물질로서 생체 내에 존재하는 전이 억제 물질이다. 본 연구는 아데노바이러스를 이용한 TIMP 유전자 치료법을 개발하여 폐암의 치료에 응용하고자 하였다. 방법 : 폐암세포는 침윤 및 전이 능력이 큰 Calu-6를 사용하였다. TIMP-2 유전자를 pACCMVpLpA에 subcloning 한 후 pJM17과 함께 293 cell에 cotransfection 한 후 homologous recombination을 이용하여 Ad-TIMP-2를 제작하였다. Ad-TIMP-2를 Calu-6 cell에 이입하여 TIMP-2 protein 이 생산되는지를 TIMP-2 ELISA를 이용하여 확인하였고 TIMP-2의 생물학적 활성은 zymography로 확인하였다. Soft agar clonogenic assay로 종양형성능을 평가하였다. Ad-TIMP-2로 처리한 calu-6를 6주간 soft agar에서 키운 후 육안으로 보이는 colony 수를 측정하였다. Matrigel을 이용하여 invasion assay를 시행하여 calu-6의 침윤 능력의 변화를 평가하였다. 결과 : TIMP-2 ELISA 결과, 모세포 calu-6와 Ad-$\beta$-gal 이입 calu-6 그리고 Ad-TIMP-2 이입 calu-6는 각각 0.44, 0.43, 20.7 ${\mu}g/10^6$ cells/72hrs의 TIMP-2를 생산하였다. Zymography 결과 Ad-TIMP-2에 의해 생산된 TIMP-2는 matrix metalloproteinase-2의 gelatin 분해 효과를 억제하여 생물학적 활성을 확인할 수 있었다. Soft agar clonogenic assay 결과, 모세포인 calu-6는 453$\pm$53개, Ad-$\beta$gal과 Ad-TIMP-2 이입된 calu-6는 각각 332$\pm$35, 280$\pm$45개의 colony가 형성되어 유의한 감소를 보이지 못했다. Invasion assay 로 모세포 calu-6 에 대한 침윤율을 평가한 결과, Ad-$\beta$gal과 Ad-TIMP-2가 이입된 calu-6(10moi)는 각각 71$\pm$8.9%, 12$\pm$8.4%의 침윤율을 보였으며 $\beta$-gal 군에 비해 TIMP-2군이 유의하게 침윤율이 낮았다. 결론 : Ad-TIMP-2는 폐암 세포의 종양형성능을 억제하지 못하였으나 침윤은 억제하여 TIMP-2가 폐암 유전자 요법에 이용될 가능성을 제시해 주었다.